Checking mechanism for controllers



Sept. 21, 1954 c. F. ROBBINS ET AL 2,639,486

CHECKING MECHANISM FOR CONTROLLERS Filed May 8, 1952 2 Sheets-Sheet l Fle.3

1mm D. MLLIAMS Sept. 21, 1954 c. F. ROBBINS ET AL CHECKING MECHANISM FOR CONTROLLERS 2 Sheets-Sheet 2 Filed May 8, 1952 mwsrvmks CLYDE f. Ross/Ms LLOYD D. WILLIAMS ,4 I i Patented Sept. 21, 1954 STATES PATENT emce- CHECKING MECHANISM FOR. CONTROLLERS- C d F- hobbins Mil kee, and Llo .1- W iams, Waukos a, s, a norS i9 Qufl H e Inc, Mil au e W s, 21, corpora,

of D a are Application May .8, 1952, Serial No. 286,735

11 Claims.

operator to move the controller to the 1' mg 5 stage. However, with such devic a 5 8;. Q impetuous operator could slam the controller through both stages without a pause in the first stage. i

The object of this invention, therefore, tp

provide a checking mechanism for a controller or the like which causes a positive pause in one stage before the controller can be advanced {to a succeeding stage even though the operator at.-

tempts to avoid such pause and which will not interfere with the automatic return .of the controller to off position, either from the first stage if the operators manually applied power is removed before advance to a succeeding stage, or from the succeeding stage if above normal operat- 'ingloads are encountered.

This object is obtained by mounting .on the oontrollershaft cam a latch or plate having a engageable with the springebiased cam -follower roller as such cam moves relative thereto from initial position to first stage. or plate under the influence of the .cam follower roller has a limited movement relative to such in a primary direction terminating in a positive roller blocking position. In such position continued pressure on the controller shaft will not result in further rotation thereof toward the second stage. Such latch or plate, however, also has movement relative to such cam in a secondary direction away from such blocking position. Movement in said secondary direction (can .occur only when the controller cam is moved slightly in a reverse direction, 1. e., away from the second stage. This reverse motionmomentar-ily removes the pressure at a high point, which otherwise =blocks the transfer of movement of such latchor plate from such primary .to such secondary dirotations and permits -a transfer spring to effect such transfer so that such plate or rlatch may move in the secondary direction to unblock fur- A sorins- 5 This latch 2. mo: mo em n of ashram a d he econd sta e- Thus the 't ollersh tt m s s me to a posit ve sto t? fi st stage b f r o ressin o th e nd.

As w b he hatt ex lained n ater dot l the iehr t wh ch normall l k t onr r ove ns o pr ma q r ot 'to h loo osit oned on the 191. he at or on ack awa of the l tween such ro er a d U on return 9 t e 1 a s e in anti u a itv in t o are cloth Th in. tion ts l how or l o h as t i s or nita andit mothod .io toget -w h a or tionel b ec s a s; s wa es thereof; i e und r t d fro l. o t ow n d. o of a spec es: omb imm otvhe r ad oimooi a with the accompanying drawings in which:

i .1 v w i side e ev tion o a heat h nism emhoduine the invention ap l d to an elect ic co ro ler. par losi g br ken my wn nsoo ionror ol itv n il us ratio this view the parts are with the controller in Off position;

Fi 2 is a vi w simila t .Eig- 1. w h t e h wn in he posi ion assumed vvh n the 03" troller is in Start'position;

Fig. 3 is a vi w smileto F .1 howing th parts in position as the controller is retracted from .the Start position of Fig. ,2;

Fig. 4 is a view similar to Fig. 1 showin the position of the pants with the controller latched in Run position;

Fig. 5 is a view. similar to Fig. 1 showing the position of the parts after the controller is latched and has movedtoward 0h" position; and

Fig. .6 is a view similar to Fig. 1 showing the position of the parts dust pri r t e ont olle .P, e et ta l n th 3 checking mechanism shown in the drawings is applied to an electric controller of well-known construction. However, the checking mechanism may be used with any controller which is operated by a rotatable shaft and in which it is desirable to check the rotation of the shaft at some point between the Oil and fully On position of the controller. In the embodiment shown, the standard parts of the controller, such as contacts, etc., have been omitted. The checking mechanism is located inside one wall III of the controller housing. This wall has a slot I2 out of which the operating lever arm I4 extends. This arm is a part of a member designated generally at I6 which is fixedly mounted on a controller shaft I8. The member I6 has a cam II along one edge which includes an Ofi position notch 26 and a first stage hump 22. The member I6 also has a locking arm 24 which is engaged by a hook 26 of a lock-in relayshown diagrammatically at 23. The controller is continuously urged'to the Off position shown in Fig. 1 by the action of a follower arm 30 pivotally mounted on the wall I I) and having a follower or roller 32 riding on the cam IT. The follower is springbiased counter-clockwise by a tension spring 34 acting between the wall I and an intermediate portion of the follower arm. The cam I! and follower 32 thus described are well-known to those skilled in the electrical controller art. Without the checking mechanism, to be hereinafter described, the controller handle is moved in a counter-clockwise direction from the Off position, which movement causes cam I1 to ride under the follower 32 until the operator feels a higher resistance to movement as the first stage hump 22 contacts follower 32.. This indicates that the controller is in the Start position and it is the duty of the operator to cease On movement of the controller at that point for sufficient time to permit the motor to pick up operating speed. Thereafter the operator by continued counterclockwise motion of the controller handle moves the controller beyond the high point of hump 22, thus providing snap movement of said handle into the Running position. In such position the locking arm 24 is engaged by the hook 26 to lock the controller in such Running position. If there should be a drop in operating voltage due to unusual conditions the relay 23 will drop out and the spring 34 acting through the follower 32 will return member I6 to the Off position shown in Fi 1.

However, many operators due to carelessness and impatience will not pause at the Start position of Fig. 2 long enough to accomplish the desired results. The checking mechanism herein described will positively stop the controller in the Start position of Fig. 2 irrespective of the will of the operator. Such checking mechanism includes a latch or plate 36 which is carried on the side of the member I6 and which has limited, guided movement relative to such member. The latch 36 is held on the member I6 by a pair of headed pins 36 and 40 passing through slots 42 and 44 in the latch 36 and rigidly secured to the member I6. The latch 36 thus slides between the side of the member I6 and the heads on the pins 33 and 40. There is a special relationship between the slot 42 and the slot 44 which permits the latch 36, under influence of a finger 46 projecting beyond cam I'I into the path of the follower32 as it moves along such cam, to be initially moved relative to the member I6 for only a short distance at the end of which such relative movement is arrested. Additional relative movement cannot occur until there has been a slight reverse movement of the member I6. Such reverse movement is utilized to permit shifting of the latch 36 so that an arresting or blocking part may clear the pin which it otherwise engages. In the embodiment shown, the slot 42 has an upper short branch 43 and a lower long branch 46 angled with respect to each other, as shown. The lower slot 44 is S-curved, as shown, and its longitudinal axis extends substantially transversely of the longitudinal axis of the short branch of the slot 42. The slot 44 has an Off notch 41 in which the pin 46 seats and a lower slope 48 leading to a high point 49 on the lower edge of such slot. The slope 48 engages the pin 40 as the latch 36 is moved from the position shown in Fig. 1 to the position shown in Fig. 2. This engagement takes place while the pin 38 is still in the short branch 43 of the slot 42. The pitch of slope 48 is steep enough to prevent the continued upward force applied by the follower 32 on the finger 46 from tilting the latch 33 about the pin 38. Hence, such initial relative movement is positively arrested when the parts reach the Starting position shown in Fig. 2. Because of. this locking action of the latch, the operator cannot continue to move the controller toward On position.

To continue movement of the controller toward Running position, it is necessary to release the latch 36 from the blocked position of Fig. 2. To do this the member I6 is retracted from the position of Fig. 2to the position of Fig. 3. This permits the latch 36 to move down relative to the member I6 and the pin 46 to ride up the slope 48. This lets the high point 49 pass under the pin 40. The pivoting action of member 36 necessary for such clearance occurs about the point of engagement between the follower 32 and the finger 46 as the center of gravity of latch 36 is to the right of such point. Thereafter latch 36 is additionally relatively moved and also pivoted from the position shown in Fig. 8 to the position shown in Fig. 4 as the member I6 is moved from Starting to Running position. During this latter movement the pin 38 travels in the long branch 45 of the slot 42 but the finger 46 keeps in contact with the follower 32. The parts are held in the Running position by the aforedescribed locking action between the arm 24 and the hook 26.

While it is in some instances practical to rely on the action of gravity on the latch 36 tocause the pivoting thereof between the positions of Fig. 2 and Fig. 3, it is advisable to utilize a transfer spring 56 which is secured to the latch 36 and to the member I6 at the angular relationship shown in the drawings. This spring, instead of gravity, cooperating with the follower 32 pivots the latch 36 about the follower 32 no matter what position the controller might be in with respect to the vertically operating force of gravity. The spring also is an assurance that incidental frictional resistance to the pivoting of the latch 36 relative to'the member I 6 will not prevent proper operation.

When the relay 28 unlatches the controller, the spring 34 acting through follower 32 on cam I! will swing the follower I6 clockwise from the position shown in Fig. 4 toward the positions shown in Figs. 5 and 6. During part of this movement the latch 36 will swing relative to the member I6 from the position shown in Fig. 4 to the position shown in Fig. 5. In order to complete Y 4 AMA gaged by follower 32 as the latter approaches Off position notch 20. The force created by such engagement carries the latch 36 inwardly so that a return slope 56 on the slot 44 leading to the Off notch 4'! of such slot rides up pin 40 and lets such notch snap into place on such pin. The pitches of slope 56 and return portion combine to produoe an upward component of force which overcomes the resistance of the transfer spring 50.

As will be apparent to those skilled in the art, cam I! may alternatively be made a stationary member, with the pivot point of cam follower 30 arranged to rotate about shaft. l8 by supporting the-same upon a suitable crank arm (not shown). With these slight modifications, the same checking action will result; wherefore this application is intended to cover all such'changes and modifications as come within the spirit of the invention or scope of the appended claims.

We claim:

1. Checking mechanism for controllers or the like comprising a controller shaft, a cam fixed on said shaft and movable forward from an initial position to a first stage and a second stage and rearward from said stages to said initial position, a cam follower biased into engagement with said cam to return said cam from said second and first stages to said initial position, a momentary pause latch movably carried by said cam and having a portion engageable with said follower upon forward movement of said cam from said initial position toward said first stage, said latch when engaged by said follower upon forward movement of said cam having limited motion with respect to said cam in a primary direction to a blocking position to positively restrain further forward movement of said cam in said first stage, said latch having additional movement with respect to said cam in a secondary direction away from said blocking position to permit movement of said cam from said first stage to said second stage, a high point operatively associated with said latch and cooperative with said follower to block the transfer of the movement of said latch from said primary direction to said secondary direction, and force means for carrying said latch over said high point to transfer the movement of said latch from said primary direction to said secondary direction upon rearward movement of said cam from its blocked position in said first stage toward said initial position.

2. Checking mechanism as claimed in claim 1 in which there are means carried by said cam and engageable by said follower upon rearward movement of said cam from said first stage into said initial position to transfer the movement of said latch from said secondary direction to said primary direction for replacement of said latch in its initial position.

3. Checking mechanism as claimed in claim 1 in which said latch has a tail engageable by said follower upon rearward movement of said cam from said first stage into said initial position to transfer the movement of said latch from said secondary direction to said primary direction for replacement of said latch in its initial position.

4. Checking mechanism as claimed in claim 1 in which said latch has a pair of spaced slots, and said cam has a pair of spaced pins each slidable in a respective slot to movably mount said latch to said cam and guide said latch in said primary and secondary directions.

6 5. Checking mechanism as-claimed in claim 4 in which one of said slotshas a first branch for guiding said latchin said primary direction and a second branch for guiding said latch in said secondary direction.

6. Checking mechanism as claimed. in claim 5 in which said high point is located in the other of said slots at a point to engage the pin in said slot and prevent the pin in the said one of said slots from entering said second branch as said latch is moved in said primary direction from initial position.

7. Checkin mechanism for controllers or the like comprising a controller shaft, a cam fixed on said shaft and movable forward from an initial position to a first stage and a second stage and rearward from said-stages to said initial position, a'cam follower biased into engagement with said cam to resiliently urge said cam rearwardly from said second and first stages to said initial position, a pair of spaced pins on the side of said cam having heads, a plate slidable on said pins between said heads and said cam, there being slots in said plate slidable along said pins, a finger on said plate in the path of said follower relative to said cam whereby said plate is moved relative to said cam as said follower travels along said path, one of said slots having a branch substantially alined with said path to guide said plate with said finger in engagement with said follower, the other of said slots having :a branch terminating in high point engaged by the pin in said slot to arrest the movement of said plate and cause said finger to stop the travel of said follower.

8. Checking mechanism for controllers or the like comprising a controller shaft, a cam fixed on said shaft and movable forward from an initial position to a first stage and a second stage and rearward from said stages to said initial position, a cam follower biased into engagement with said cam to resiliently urge said cam rearwardly from said second and first stages to said initial position, a plate on the side of said cam having a pair of spaced guiding slots, pins on said cam extending into said slots to guide said plate, a part of said plate projecting into the path of travel of said follower relative to said cam, one of said slots having a sloping portion engageable with the pin in said one of said slots to arrest the movement of said plate by said follower, and means cooperable with said follower upon the reverse movement thereof to swing said plate so that said portion passes beyond said one of said ins.

9. Checking mechanism for controllers or the like comprising a controller shaft, a cam fixed on said shaft and movable forward from an initial position to a first stage and a second stage and rearward from said stages to said initial position, a cam follower biased into engagement with said cam to resiliently urge said cam rearwardly from said second and first stages to said initial position, a plate on the side of said cam having a pair of spaced guiding slots, pins on said cam extending into said slots to guide said plate, a part of said plate projecting into the path of travel of said follower relative to said cam, the upper slot having a short branch and a long branch arranged at angles with respect to each other, the lower slot being reverse curved and extending transversely of said short branch, there being a high point in said lower slot between the ends thereof, said high point being spaced with respect to said short branch whereby upon engagement of the pin in said lower slot with the side of said high point the pin in said upper slot will remain in said short branch and movement of said plate arrested.

10. Checking mechanism as claimed in claim 9 in which upon reverse movement of said cam said cam will swing said high point past the pin in said lower slot and the pin in said upper slot will move into said long branch and permit further movement of said plate upon forward movement 10 of said cam. V

11. Checking mechanism for controllers or the like comprising a cam and a cam follower, means providing for relative movement between said cam and said cam follower from an initial position to a first stage and a second stage, biasing means tending to effect relative movement between said cam and said cam follower from said second and first stages to said initial position, a

plate'on the side of said cam having a pair of spaced guiding slots, pins on said cam extending into said slots to guide said plate, a part of said plate projecting into the path of travel of said follower relative to said cam, one of said slots having a sloping portion engageable with the pin in said one of said slots to arrest the movement of said plate by said follower, and means cooperable with said follower upon reverse movement thereof to swing said plate so that said portion passes beyond said one of said pins.

References Cited in the file of this patent UNITED STATES PATENTS 

